Date of Award

Spring 5-15-2020

Author's School

McKelvey School of Engineering

Author's Department

Mechanical Engineering & Materials Science

Degree Name

Master of Science (MS)

Degree Type

Thesis

Abstract

In recent decades, Computational Fluid Dynamics (CFD) has become the most widely used technology to understand the fundamental complex fluid dynamics of turbulent flows as well as for modeling of turbulent flows in industrial applications. In industrial applications, the widely used methodology is to solve Reynolds-Average Navier-Stokes Equations (RANS) equations in conjunction with a turbulence model since it strikes a balance between accuracy and computational cost compared to other high fidelity approaches namely the Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS), There are a large number of turbulence models proposed in past five decades, majority of them are linear eddy viscosity models based on the Boussinesq’s hypothesis. Among these, the one equation Spalart-Allmaras (SA) and Wray –Agarwal (WA) model and two equations k-ε, k-ω and SST k-ω are most popular. Most of these models suffer from two drawbacks: (1) they have stress-strain misalignment in the near-wall region due to Boussinesq’s hypothesis and (2) they contain wall distance as a parameter in the model which can introduce error in case of complex boundaries especially with the use of unstructured grids. The goal of this thesis is to address these two drawbacks in the standard k-ω SST model. The first issue is addressed by combining the k-ω SST model with the elliptic blending lag equation to correct the stress-strain misalignment and the second issue is addressed by developing a wall distance free k-ω SST model. The newly developed models are validated on several benchmark test cases given on NASA Turbulence Modeling Resource (TMR) website for both external and internal wall-bounded flows with small regions of separation. The computations show that both models can provide better agreement with the experimental data compared to the original k-ω SST mode

Language

English (en)

Chair

Dr. Ramesh Agarwal

Committee Members

Dr. David Peters Dr. Swami Karunamoorthy

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